Power overload situations and unwanted resonance scenarios regularly occur within the field of wind turbine related energy supply. An overload situation occurs when a required amount of electrical power exceeds the nominal power level of the power distribution network delivering the power. In order to handle such overload situations the power distribution network must have access to available power reserves. Unwanted and disturbing resonance scenarios may be caused shifting impedance and may occur within a wind turbine facility or between a wind turbine facility and an associated power supply grid.
Overload capacities of power converters for wind turbine systems are typically established by overrating semiconductor switch components for higher continuous operating current. Alternatively, additional semiconductor switch components are added to provide a required overload capacity. However, additional switch components increase the overall losses of the converters.
It is a drawback of the above-mentioned conventional solutions that the costs of components and thereby the costs of manufacturing are high. Moreover, increased electric losses are related to the above-mentioned ways of establishing a required overload capacity. Also the addition of more components increases the risk of a component failure.
WO 2005/027301 deals with a method for handling low voltage ride through events where a DC/AC converter is operated with a reduced switching frequency in order to pump additional current into a power supply grid in case the grid voltage drops significantly.
It may be seen as an object of embodiments of the present invention to provide an arrangement and an associated method for establishing overload capacities without increasing the complexity and the costs of manufacturing of a power converter.
It may be seen as a further object of embodiments of the present invention to provide a reconfigurable arrangement being capable of avoiding or suppressing internal resonances/harmonics within a wind turbine and external resonances/harmonics between a wind turbine and some external devices.